Class Response: The Earth's Atmosphere

In class, we began learning about the Earth's atomosphere, and its layers. The atmosphere is divided into five layers; troposphere, stratosphere, mesosphere, and the thermosphere, which has two parts, the ionosphere and exosphere. The atomosphere is thickest near the surface and thins out until it eventually merges with space. The troposphere is where all weather takes place, and is the layer we basically live in. All the rain, snow, wind, etc. occurs in this layer. Next, is the stratosphere is where the temperature increases with altitude. The thin ozone layer in the upper stratosphere has a high concentration of ozone, a reactive form of oxygen. Ozone is concentrated around an altitude of 25 kilometers. This layer is mostly responsible for absorbing the ultraviolet radiation from the sun. In the Earth's mesosphere, the air is relatively mixed together and the temperature decreases with altitude. The atmosphere reaches its coldest temperature of around -90°C in the mesosphere. This is also the layer in which a lot of meteors burn up while entering the Earth's atmosphere. Above the mesosphere is the ionosphere, the lower part of the thermosphere. where many atoms are ionized, which means they have gained or lost electrons so they have a net electrical charge. Scientists call the ionosphere an extension of the thermosphere, so technically the ionosphere is not another atmospheric layer. The ionosphere is very thin, but it is where auroras take place. Very high up, the Earth's atmosphere becomes very thin. The region where atoms and molecules escape into space is referred to as the exosphere, which is the upper part of the Earth's thermosphere. Thats what I've learned in class, and I hope all of that information enlightened you too! =]